Question

start writing a mathematical equation by writing an expression that represents the cost of c candles. cost of candles + cost of journals = $35 \square +? =?

Explanation:

Step1: Define candle cost variable

Let the cost per candle be $p$. The total cost of $c$ candles is the product of the number of candles and the cost per candle.
$\text{Cost of } c \text{ candles} = p \times c = pc$

Step2: Substitute into given equation

Replace the "cost of candles" placeholder with the expression for the total cost of $c$ candles, and keep the known total value.
$pc + \text{cost of journals} = 35$

Answer:

The expression for the cost of $c$ candles is $\boldsymbol{pc}$ (where $p$ is the cost per candle), and the completed equation is $\boldsymbol{pc + \text{cost of journals} = 35}$